This invention relates to an adhesive system and more particularly to an adhesive system for bonding a plastic structural member to the upper and lining of a shoe to form a boxtoe, which is a stiffening component for footwear.
Boxtoes are formed in the toe portion of shoes and boots. The boxtoe structure may include a formable plastic member made of, for example, an alloy of an ionomer and a high impact polystyrene. This plastic member is coated with a material which, when activated, becomes tacky so that it may be adhered between an upper and a lining of the shoe.
Heretofore, the coating on the boxtoe component included styrene saturated products and thermoplastic ABS alloy which are activated by contact with solvents such as toluene, methylene chloride and methyl ethyl ketone. These solvents are highly volatile and pose a risk to the environment and to the personnel who must handle them in the shoe factory environment.
Another boxtoe adhesive system is known in which the adhesive coating is activated by immersion in hot water. This system thus requires the considerable energy expenditure necessary for heating water.